The invention relates to bearings generally, and antifriction bearings more specifically.
Antifriction bearings come in a variety of types, but typically fall into two categories, namely, ball bearings and roller bearings. Both types of bearings operate according to a similar principle, namely, rolling motion of rolling elements, such as balls or rollers, between rotating and stationary members. The rolling motion is utilized to reduce friction, and thus, the term “antifriction” is used.
Bearings are classified according to their ability to sustain radial and thrust loads, as well as combined radial and thrust loads. In addition, the shape of the rollers or balls determine bearing classification. Rolling element shapes include: spherical, cylindrical, tapered, and needled.
In the design of roller bearings, a continuous goal is to extend the useable life and enhance the overall performance of the roller bearing. Typically, a cage structure is used to separate and contain the rollers within a bearing. The result is increased friction and vibration generated between the rollers and the cage because of the contact between the rotating rollers and the relatively static cage. Such increased friction and vibration result in increased temperature and noise.
Therefore, it would be desirable in the commercial bearing industry for the roller bearing to decrease the friction and vibration caused the elements in the bearing assembly, thereby decreasing temperature and noise, as well as wear of the bearing, and increasing the life and performance of the bearing. It would also be desirable to decrease the extent of direct contact between rolling elements and the cage structure.
It would be particularly desirable to enable a bearing to accommodate rolling elements that are adjacent to and, when in a dynamic state, in rolling contact with each other. In this instance, the elements that are adjacent and in rolling contact can be termed “counter-rotating.” There is specific need in the industry for bearings having counter-rotating rolling elements so as to achieve the goals noted above.